The output is a numeral, not a different quantity. FE in this result means base 16; without context, the text “10” could mean decimal ten or hexadecimal sixteen. Add a label or conventional 0x prefix when sharing the value in technical work.
Leading zeros do not change an integer’s value, so 00FF and FF both represent 255. They can still matter in a fixed-width field: a byte is often displayed as two hexadecimal digits. This page removes such formatting and returns the shortest numeral.
Do not treat the letters as variables or ordinary text. Each is one digit with a defined numeric value.
Checking with binary groups
You can verify a hexadecimal result through binary. Replace each hex digit with four bits: 0 through F correspond to 0000 through 1111. For example, 2A becomes 0010 1010. Reading that binary value as decimal gives 32+8+2=42. This method is especially convenient for byte values, where two hex digits cover eight bits.
Fixed width and overflow
The mathematical conversion has no chosen byte width. Software storage does. Decimal 300 converts correctly to hex 12C, but it cannot fit in one unsigned byte because one byte stops at FF, or 255. Decide the required storage width separately and add leading zeros only after conversion. For example, a 16-bit display might write 42 as 002A. The calculator’s shorter 2A has the same numeric value.